1. Field of the Invention
The present invention relates to a clutch for a compressor, and more particularly, to a non-contact type clutch for a compressor, installed on a rotary shaft of a compressor in an air conditioning apparatus for an automobile, for temporarily suspending power transmitted from a driving source to the rotary shaft.
2. Description of the Related Art
A compressor used in an air conditioning apparatus for an automobile is driven by receiving power from an engine of the automobile. Thus, it is necessary to temporarily suspend the power transmitted from the engine to the rotary shaft of the compressor. An electromagnetic clutch installed on the rotary shaft of the compressor performs the interruption.
FIG. 1 shows an example of a conventional clutch.
As shown, the conventional clutch for a compressor includes a pulley 13 installed on a rotary shaft 12 of a main body 11a of a compressor 11 and having a housing portion 13a and a frictional surface 13b formed on rear and front surfaces thereof, and an electromagnet assembly 14 fixed on the main body 11a and having an electromagnet 14a received in the housing portion 13a.
A hub 15a is fixed on the rotary shaft 12. The hub 15a is coupled to a stopper plate 15. In the stopper plate 15, a disk 17 is spaced apart a predetermined distance from the frictional surface 13b by supporting means 20.
The supporting means 20 includes a rivet having a head 22a coupled to a plurality of throughholes 21 formed on the stopper plate 15, and the rivet 22 passes through the throughholes 21 to be riveted into the disk 17. A damper 23 made of rubber is adhered by an adhesive agent between the outer surface of the rivet 22 and the inner surface of the throughholes 21.
In the operation of the conventional clutch 10, the disk 17 is tightly coupled to the frictional surface 13b of the pulley 13 by a magnetic force generated when a predetermined current is applied to the electromagnet 14a. Thus, the rotational power of the pulley 13 rotated by the engine is transmitted to the rotary shaft 12.
When current does not flow in the electromagnet 14a, the disk 17 is separated from the frictional surface 13b of the pulley 13 due to elasticity of the damper 23 installed on the head 22a of the rivet 22 so that the rotational power of the pulley 13 is not transmitted to the rotary shaft 12 and the pulley 13 is raced.
In the operation of the clutch, when the rotary shaft 12 rotates at a high speed, the damper 23 positioned between the head 22a of the rivet 22 and the upper surface of the stopper plate 15 may be detached from the rivet 22. Also, since the damper 23 protrudes from the upper surface of the stopper plate 15, the overall compressor is relatively bulky.
Another conventional clutch (not shown), as disclosed in U.S. Pat. No. 5,687,823 (FIG. 1), includes a hub installed on a rotary shaft and having a predetermined width, a holder spaced apart a predetermined distance from the hub and coupled to a disk, and an elastic member interposed between the hub and the holder, for supporting the hub and holder. However, according to this technology, since the outer peripheral surface of the hub and the inner peripheral surface of the holder are adhered to the elastic member by an adhesive agent, the fabrication process is complex. Also, since the elastic member is integrally adhered between the outer peripheral surface of the hub and the inner peripheral surface of the holder in a ring shape, the frictional heat generated when the disk rotates at a high speed is directly transmitted to the elastic member. Thus, the adhesive strength becomes weak by the frictional heat so that the contact portion may become disjoined, which is an obstruction to the durability of the compressor.
In such conventional clutches, since the inner and outer rings have a predetermined width, the clutch is thick, thus the space required for installing the clutch in a compressor increases. Also, the weight of the clutch may increase due to a damper.